Process for the production of a tube for the bundled guidance of an electron beam



Dec. 12, 1967 E. ACHTER ETAL 3,357,096

PROCESS FOR THE PRODUCTION OF A TUBE FCR THE BUNDLE!) GUIDANCE OF AN ELECTRON BEAM Filed Sept. 29, 1965 Fig.1

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United States Patent l 3,357,996 IRGCESS FOR THE PRODUCTION OF A TUBE FOR THE EUNDLED GUIDANIIE (IF AN ELEC- TRON BEAM Eugen Achter and Paul Kahl, Munich, Germany, assignors to Siemens dz Halshe Alctiengeseilschaiit, Berlin and Munich, Germany, a corporation of Germany Filed Sept. 2?, 1965, Scr. No. 491,460 Claims priority, application Germany, Sept. 30, 1964, S 93,461 4 Claims. (Ci. 29-592) The invention relates to a process for the production of a tube consisting alternately of soft-magnetic and nonmagnetic rings, which, for the bundled guidance of an electron beam Within a magnetic system which at least partially encloses the electron beam.

Permanent magnet systems are already known for the generation of a periodic magnetic system for the bundled guidance of the electron beam of discharge tubes, especially traveling wave tubes. These known systems contain permanent magnets arranged symmetrically to the electron path, as well as pole shoes which are arranged one after the other in electron beam direction, through which the electron beam passes. The pole shoes there connect oppositely disposed like poles of the permanent magnets.

It has also been proposed for a permanent magnet system of the known type mentioned, that Within the mag netic system the electron beam be enclosed at least for a portion of its travel by a tube which consists alternately of soft-magnetic and non-magnetic rings.

In this construction, soft-magnetic rings of an odd ordinal number border immediately on the pole shoes and are symmetrically surrounded thereby, while softmagnetic rings of an even ordinal number in each case, as viewed in electron beam direction, are centrally arranged between adjacent pole shoes. In a tube constructed in this manner defects in the rotational symmetry of the magnetic field which are due to the unavoidable production tolerances of the known magnetic systems for the generation of a periodic magnetic field are compensated. In particular, the soft-magnetic rings of an odd ordinal number eliminate asymmetries of the magnetic conduction field, which occur by reason of manufacturing imprecisions of the pole shoes in their immediate vicinity. The soft-magnetic rings arranged between the pole shoes compensate such transverse fields as may be caused by defects in the spatial arrangements of the pole shoes and by inaccuracies on the end face of the pole shoe.

In the proposed arrangement, the tube, which consists alternately of soft-magnetic and non-magnetic rings can efiiciently fulfill its purpose, namely that of eliminating disturbances in the rotational symmetry of the magnetic field, only if the individual rings extend precisely perpendicular to the axis of the electron path and have, in axial direction, bordering edges which extend exactly parallel to one another. It has now proved that these requirements cannot be sufiiciently Well satisfied Without dii'ficulty if the tube is soldered or cemented together out of individual prefabricated rings. In order to overcome this difiiculty, in a process of the type initially mentioned, it is proposed that a cylinder of soft magnetic material first be provided with annular grooves and that such grooves thereafter be filled with a non-magnetic material, whereupon the tube can be produced from the cylinder with the desired internal and external diameters.

The process according to the invention assures, with any desired reproducibility, that in a tube produced according to this process the individual magnetic and nonmagnetic rings are aligned extraordinarily accuartely perpendicularly to the axis of the tube. As material for the 3,357,096 Patented Dec. I2, 1967 cylinder there is, preferably employed, soft iron, the grooves in which are advantageously filled with copper.

The invention will be explained in detail with the aid of the figures of the drawing, in which:

FIGURE 1 is a longitudinal section of a cylinder blank of magnetic material, having annularly shaped non-magnetic inserts; and

FIGURE 2 is a side elevation of a tube formed from the cylinder blank illustrated in FIGURE 1.

FIGURE 1 illustrates a solid cylinder 1 consisting of soft iron. Into the iron cylinder 1 there are turned by a lathe annular grooves or channels 2, which are completely filled with copper. The copper is there preferably cast into the grooves 2 or introduced galvanically. The copper may, however, also be soldered into the incisions 2 in the form of copper disks or plates.

The tube is finally formed from the stock blank illustrated in FIGURE 1 with the desired internal and external diameters, as indicated by the broken lines 3. For a better understanding, in FIGURE 2 a finished tube is illustrated, which has been produced :from the work piece of FIGURE 1, for example, by a simple lathe operation. Measurements have shown that this tube, which now consists alternately of soft-magnetic and non-magnetic annular sections 4 and 5, is considerably superior in its manufacturing tolerances to a tube which is built up of individual iron and copper rings stacked upon one another and soldered together.

The invention is not limited to a process for the production of a magnetic guide tube for a permanent magnetic system of the type initially described. On the contrary, a tube produced according to the invention can be used to advantage in any magnetic system in which troublesome magnetic transverse components are to be compensated. In particular, if only disturbances in the rotational symmetry of the magnetic field are to be compensated which are due to the nature of the pole shoes, the annular sections of the tube can be so dimensioned that in a corresponding magnetic system the soft-magnetic rings are merely disposed within the individual pole shoes.

Changes may be made within the scope and spirit of the appended claims which define what is believed to be new and desired to have protected by Letters Patent.

We claim as our invention:

1. A process for the production of a tube consisting alternately of soft-magnetic and non-magnetic rings, which tube, for the bundled guidance of an electron beam, at least partially encloses such an electron beam, comprising the steps of forming annular grooves in a cylinder of soft-rnagnetic material, entirely filling said grooves with a non-magnetic material, and thereafter processing said cylinder to form a tube with the desired internal and external diameters.

2. A process according to claim 1, wherein the cylinder consists of soft iron and copper is disposed in the grooves.

3. A process according to claim 2, wherein the copper is cast into the grooves.

4 A process according to claim 3, wherein the tube is produced from the iron cylinder by a turning operation on a lathe.

References Cited UNITED STATES PATENTS 2,911,554 11/1959 Kompfner et al. 3,219,557 ll/1965 Quintana. 2,834,095 5/1958 Lazzopina et al. 29-597 X JOHN F. CAMPBELL, Primary Examiner.

D. C. REILEY, Assistlant Examiner. 

1. A PROCESS FOR THE PRODUCTION OF A TUBE CONSISTING ALTERNATELY OF SOFT-MAGNETIC AND NON-MAGNETIC RINGS, WHICH TUBE, FOR THE BUNDLED GUIDANCE OF AN ELECTRON BEAM, AT LEAST PARTIALLY ENCLOSES SUCH AN ELECTRON BEAM, COMPRISING THE STEPS OF FORMING ANNULAR GROOVES IN A CYLINDER OF SOFT-MAGNETIC MATERIAL, ENTIRELY FILLINGS SAID GROOVES WITH A NON-MAGNETIC MATERIAL, AND THEREAFTER PROCESSING SAID CYLINDER TO FORM A TUBE WITH THE DESIRED INTERNAL AND EXTERNAL DIAMETERS. 